This thread is a lot more of a compilation of what's out there instead of a value judgment as to what is more or less effective.

To both the trainers here, and the students, I think it's important to at least have a basic familiarity with what methods have been previously devised.
By doing so, when someone asks, you can intelligently offer a opinion like:
"Keller Technique sucks because of x, y, and z....
"FBI Technique is good in these circumstances and bad in these circumstances....
"Hargreaves Lite-Touch worked/didn't work for me because....
"Etc., etc, etc."

So here are some videos I produced to illustrate this:

First: 14 Different Grips quickly run through one after another:
http://www.youtube.com/watch?v=HZRNLfbnIJM

Second: The compendium plus all the individual techniques in a scrolling playlist so you don't have to hunt for the more detailed individual videos:
http://www.youtube.com/user/Frankdude72#grid/user/5CD91F111D5E2A41

•A lot of this footage was taken over 2 years ago, and several of those shooting sessions was myself and friends trying the grips for the very first time.

-(In contrast, the FLUSA Liberator videos were done quite recently.
After taking some excellent moving while shooting training with Suarez International, it was a matter of forcing myself to stand still and/or keep the light on very long so that hits could be illustrated using the given specific grip.)

-So please bear in mind this isn't some advanced tactical flashlight video, but something to help get people familiar with a variety of extant methods.

•Having recently done a room clearing Force-On-Force class
(SouthNarc's Armed Movement in Structures
http://www.shivworks.com/ )
with a night element, my opinions have shifted of late.
-These days I'm much more in favor of using something FBI Technique-ish to quickly illuminate a dark corner in a structure and then afterwards moving just as quickly away from where you shined the light.
-I'm now much less likely to want to do a "hands together" technique while shining the light itself when choosing to put both gun and flashlight hand together.
-This opinion is, of course, subject to change or to be reinforced with future experience and information.

•Speaking of FBI Technique, the way I've illustrated it here, and recommend implementing it, is more conceptual than rigid.
-I'm aware of some debate over FBI and Modified FBI and advocacy of different flashlight hand positions.
-My personal take on it is to conceptually keep the flashlight away from your body, and hold it at an appropriate angle to hastily peer into said dark corner.

-Eight of these grips
(Harries, Marine Corps, Chapman, Ayoob, FBI, Hargreaves, Keller, and Neck-Index)
can be found in Ken J. Good's article "Handgun Flashlight Techniques" in the November 2002 issue of Guns&Ammo SureFire Presents Combat Tactics.
We used this article extensively as a reference.

-Upon mentioning this article, it should be noted that the photos of the Chapman and Ayoob Techniques didn't match the text descriptions.
This is especially frustrating when you're sitting in the countrified pitch dark and trying to discern what the author is writing vs. what one is seeing pictured.
So my apologies if those 2 grips are not 100% representative of of their developer's intent.
For the still pictures I made every attempt to get them more accurate, and so also used this website as a reference:
http://www.nrapublications.org/si/HB_handgun.html

-For the live fire of the Pincus/Valhalla technique, I must admit we probably didn't angle the light low enough and possibly shot at distances beyond the method's intent.
That said, for the still pictures, I again made every effort to get both stages of this technique done as Rob Pincus illustrates here:
http://www.imakenews.com/valhalla/e_article000413118.cfm?x=b11,0,w

-I make no secret that I personally prefer the configuration of the First-Light USA flashlights (especially the Tomahawk), but I endeavored to not make this thread a blatant advertisement for their products.
My bias is there, but you decide on what you select for yourself.

-Hargreaves Lite-Touch was called Fuentes when I attended a Urban Rifle class Thunder Ranch Texas.
In that context, it was pressing the tailcap against the magwell of an AR/M4-style rifle.

-Although noted in the 14 Grip compendium video, some may point out my omission of the Finger Ring Technique/Graham Method.
Please examine the Hargreaves Lite-Touch.
They are essentially the same.
A rear mounted finger ring on a tube light only adds some retention — and perhaps some stability — versus doing the Hargreaves without a ring.

Ok everyone, hope this has been helpful and informative.

At the very least, I hope those instructors out there will have a reference in case any students ask about something obscure.